Half to chester bradford



3 Sheets-Sheet 1.

(No Model.)

G. N. LEONARD.

DRAWING BOARD.

No. 324,855. Patented'Aug. 25, 1885m WITNESSES. 29 2? IN VEJVTOR.

N. PETERS. Phola-Uflwprapher. Washington. 0. c.

(No Model.) 3 SheetsSheet 2.

v C. N. LEONARD.

DRAWING BOARD.

No. 324,855. Patented Aug. 25, 1885.

N. PETERS. Pimm-Lnnv mr. wmzn xon, u c.

(No Model.) 3Sheets-Sheet 3. U. N. LEONARD.

DRAWINGBOARD.

,855. Patented Aug. 25, 1885.

WITNESSES.

rrn

CHARLES N. LEONARD, OF INDIANAPOLIS, INDIANA, ASSIGNOR OF ONE HALF TO CHESTER BRADFORD, OF SAME PLACE.

DRAWING-BOARD.

ASPECIPICATION forming part of Letters Patent No. 324,855, dated August 25, 1885.

Application filed April 5, 1884. (No model.)

To all whom it may concern:

Be it known that I, CHARLES N. LEONARD, of the city of Indianapolis, county of Marion, and State of Indiana, have invented certain new and useful Improvements in Drawing- Boards, of which the following is a specification.

My said invention consists in various improvements in the construction of drawing boards whereby a board is provided with which the use of angles is unnecessary in making drawings, and one which has means for read ily and easily securing the drawing -paper thereto and removing it therefrom without the use of the ordinary thumb-tacks, with various other advantages, all of which will be hereinafter more particularly set forth.

Referring to the accompanying drawings, which are made apart hereof, and on which similar letters of reference indicate similar parts, Figure l is a perspective view of my improved drawing-board ready for use; Fig. 2, a perspective view of the under side of the board, the side pieces being shown in dotted lines; Fig. 3, an under side plan of said board; Fig. 4, a central vertical section of the same on the dotted line 2 z,- Fig. 5, a view similar to a portion of Fig. 4 on an enlarged scale; Fig. 6, a detail section on the dotted line y y in Fig. 3; Fig. 7, a detail section looking to the right from the dotted line 00 in Fig. 8; Fig. 8, a detail section on the dotted line to w in Fig. 3; Fig. 9, a detail section on the dotted line o o in Fig. 4; Fig. 1.0, a detail section on the dotted line a a in Fig. 9; Fig. 11, a detail section on the dotted line t t in Fig. 4; Fig. 12, a similar section on the dotted line 8 s in Fig. 3; Fig. 13, a detail section looking upwardly from the dotted line rr in Fig. (3; Figs. 14' and 15, top or plan views illustrating several positionsin which the board maybe placed. Fig. 1.6, an alternate construction of the mechanism for operating the clamps that hold the paper in place, showing straight levers instead of bellcrank levers and coni'iectingrods, and Fig. 17 a section ofthe same, looking upward ly from the dotted line q q' therein.

In said drawings the portions marked A represent the frame in which the board is mounted; B, said board; 0, a set-screw for rigidly securing the board in any desired pot sition; D, a catch for stopping and holding the board at any of the different angles; E, clampbolts for holding the paper in place on the board; F, bell-crank levers to which the clam pbolts are attached; G, a belt for operating the mechanism; H, other bell-crank levers, one arm of which is attached to said belt; I, rods connecting the projecting arm of the bellcrank levers which connect with the clamp-bolts E to the corresponding arm of the bell-crank levers which connect with the operating-bolt G, and J a sheet of paper secured to the board by my improved means.

(usually the left-hand side) is made straight and true to serve as a guide for the draftsmans T-square, and is usually rectangular, as shown, although the form of the other sides is not material. It is provided with a circular opening for the board, as shown. On the top and next the edge of the opening the degrees of a circle are preferably indicated, and thus the operator is enabled to adjust the board to any angle desired. Antifriction rollers A are journaled in bearings a on the under side of the top and next the opening, the rollers extending out under the board and being adapted to support it. A piece, A, extends across between the side pieces under the center of the board having a bearing, a, set there in directly under the center of the board, in which said board is pivoted, as will be presently described.

The board B is circular in form and adapted to fit into and revolve in the opening in the top of the frame, it being supported at its edges by the anti-friction rollers A, as before described, or as may be desired. It is preferably composed of several thicknesses of wood, which are arranged to cross the grain of each other and thus make the board stiff and less liable to warp or shrink. It is preferably further stiffened by a metal spider or plate, B, seen red to its under side. Theccn ter of said spider or plateis located under the exact center of the board, and is extended into a pivot, I), which sets into the bearing a on the cross-piece A Said pivot extends down through said bearing and is hollow. A washer, b, is secured on the end of the pivot by the screw 1), and the board is thus secured in The frame A has a top, one side of which place. Indicator-marks b are inscribed on the board at opposite edges in line with the center of the drawingpaper and of the mechanism of the board, for the purpose of indicating on the degree-circle the angle at which the drawing-paper is placed. Said board is also provided with notches 1) around its edge, (preferably in the form of holes through adjustable plates 12 with which the catch D engages and holds said board in place, as will be hereinafter described.

The set-screw O operates in a nut, c, which is set in the edge of the frame and screws in against the friction-plate c, which bears against the edge of the board, as shown,(see Fig. 11,) and thus rigidly secures the board in any position desired. It is shown as being placed at the head of the board opposite the operator; but it can be placed on either side, if preferred, as will be readily understood.

The catch D is set in an opening in the edge of the frame, and is adapted to engage with the notches b in the edge of the board. It is preferably a spring-catch, as shown, (see Fig. 9,) and is operated by a lever, D, to which it is connected by the link (I. Said lever D is mounted on the pivot d between lugs on the plate D said plate D being set into the edge of the frame next the operator and provided with an opening through which a thumbpiece, (1 on the end of the lever D extends. A sliding stop, D is secured to the inside of the plate D", and a lug, (Z is formed on the thumb-piece d Thus when it is desired to hold the catch out of engagement with the notches in the edge of the'board, the thumb-piece is pushed in, which operates to disengage the catch, the lug being at the same time forced inside the plate, and the stop, by means of its projection d", is slid under said lug, which holds the catch from being thrown back into engagement with the board until the stop is slid back from under said lug.

The clamp-bolts E are arranged one at each corner of the drawing-paper. Their top parts or heads are formed thin and fiat, and are formed mostly on one side of the bolt. At the upper end of the holes for these bolts shallow depressions are formed in the board, as shown in Figs. 6, 7, and 8, so that the heads or clamps will not come above the surface of the board after the paper is in place, and thus be in the way of the T-square in making the drawing. Each bolt extends down through the board and connects with one arm of the bell-crank lever F, to which it is adjustably secured by the thumb-nut e. A spring, E, is secured to the board and one end is bifurcated and adapted to straddle thc'neck of the thumbnut e and bear upwardly against it, thus keeping the clamp up free from the board,except when drawn down by the mechanism, as will be presently described.

The bell-crank levers F are mounted on pivots f in the bearings E, which are secured to the under side of the board near each hole for the clamp-bolts and in line with said hole and the hole for the operating-bolt at the opposite end of the board. One arm of said 1ever lies parallel with the board and connects with the elamp-bolt,'and the other stands out from said board and is adapted to have one end of the rod I pivoted thereto.

The operating-bolt G extends up into an aperture formed in the top side of the board to receive it and the thumb-nut g, which operates upon it. The head is preferably elongated and extends out over the horizontal arms of the bell-crank levers, which are located each side thereof. The third or middle bell-crank lever extends under the center of the head, and preferably astride the bolt. This b0lt-head preferably has pins 9 on its ends, which are adapted to engage with holes or slots in the horizontal arms of the two bellcrank levers atthe sides, and thus are more certainly engaged to said bolt-head, and also prevent the bolt from turning as the thumbnut g is operated.

The bell-crank levers H are mounted on pivots h in the bearings H. One of said bellcrank levers is placed on the side of the bolt next the center of the board, and is adapted to have two rods connected to its projecting arm; The end of the other arm is bifurcated and is placed astride the bolt G under its head. The other bell-crank levers are placed on each side of the bolt and between said bolt and the clamp-bolts of the end of the board in which this bolt is located. Their horizontal arms have holes or slots provided in their ends, into which the pins formed on the head of the bolt, enter.

The connecting-rods I connect the projecting ends of the bell-crank levers F to the projecting ends of the bell-crank levers H. The two long rods connect each of the two levers which operate the clamp-bolts at the lower end of the board to the one lever in the center of the board at the upper end, and each of the two short rods connects one of the levers which operate the clamp-bolts at the upper end of the board to the lever on its own side which connects with the bolt G. (See especially Fig. 3.)

In cases where desired the bell-crank levers and connecting-rods may be dispensed with, and the levers I, as shown in Figs. 16 and 17, substituted; but this, while the simpler, is the heavier and more cumbersome construction, and I therefore prefer that illustrated in the principal drawings.

The operation of my said invention may be briefly recapitulated as follows: The board being in condition for use, as shown in Fig. 1, and it being desired to make lines of any angle, the catch D is disengaged from the notch in the edge of the board by pushing in the thuinbpiece (F. The board is then turned until the indicator at the top of the board points to the angle desired, when the catch, being released, will engage with another notch and hold the board in this position until it is again desired to change the angle, when it is done in the same manner as before. If it happens to be an odd angle for which no notch is provided in the edge of the board, the stopscrew 0 is turned in, which bears the frictionplatcc against the edge of the board, and thus holds said board in the desired position. This stop-screw is also used when for any other reason it is desired to hold the board perfectly rigid. The paper is released by turning back the thumb-nut g, which relaxes the grip and permits the springs E to operate to raise them up free from the paper. Said paper is secured in position by the reverse operation of the thumbnut, which draws the bolt G up, which operates to pull down the arms of the bell-crank levers to which it is attached and the other arms forward, which operation, through the connectingrods I and the other bell-crank levers, F, draws down the clampbolts tightly and secures the paper in position. If they should not clamp evenly, they can be easily adjusted to do so by the thumbnuts e, and if the connecting-rods I do not pull evenly they can be readily adjusted by the nuts 1' upon their ends, (see Figs. 3, 5, and 6,) as will be eadily understood.

If it is desired, the rods can be divided and a turn-buckle placed in the middle for making this adjustment; or one end of the rod can be provided with a head engaging with one bellcrank lever, and the other screw-threaded and enter a clevis pivoted to the other bcllcrank lever of the two which are connected thereby.

My invention is designed especially for use where all drawings made are of uniform size, as is the case with drawings for Patent Office purposes, and by its use the use of angles is n ale unnecessary in making the drawings, and the draftsman is enabled to havehis work in any position he may desire without changing its position upon the board or the position of his square. The use of thumb-tacks is also avoided, and an easy and quick means for securing the drawing-paper in position is provided.

Having thus fully described my said inven tion, what I claim as new, and desire to secure by Letters Patent, is

1. The combination of the frame A, one side of which is adapted to serve as a guide for a draftsmans square, the circular revoluble board B, mounted in an opening in said frame and provided with notches in its periphery, and a catch secured to said frame and adapted to engage with said notches, whereby said board can be secured in any of several certain positions relative to said frame, and the drtuving-paper on said board thereby given the desired secure but adjustable relation to the guide side of said frame.

2. The combination of the frame A, having one side adapted to serve as a guide for a draftsmans square, the circular revoluble board. 13, mounted in an opening in said frame and provided with notches in its periphery, a catch, I), secured in the edge of the opening in said frame, and a lever, D, one end of which is attached to said catch, and the other end of which extends out to the outside edge of said frame, whereby said catch em be operated, substantially as set forth.

3. In a drawingboard, the combination of the revoluble board having notches in its edge. the frame in which itis mounted having one side adapted to serve as a guide for a draftsmans square, the spring-catch D, so cured to the edge of the opening in said frame and extending against the edge of said board, and the lover I), connected to the free end of said catch and extending at its other end out through said frame and having a thumb-piece, (1, formed on said end, whereby said catch can be readily disengaged from the edge of theboard from the outside edge of the frame, substantially as set forth.

4. In a drawing-board, the combination of the frame A, circular board B, pivoted in a circular opening therein, catch D, securedto the inside edge of the frame, the lever D, pivoted on the plate D and connected to the catch by a link, (1, and said plate D", substantially as set forth.

5. In a drawing-board, the combination, with the board B and frame A, of the catch D, secured to the edge of said frame and adapt ed to engage with notches in the edge of the board, thelever D, pivoted in hearings on the plate D and connected to the catch by the link d, and the plate D, said plate having an aperture through which a thumb piece, (P, on one end of said lever 1) projects, and also having a slide, 1), which is adapted to be slid under a lug on said thumbpieee when said thumb-piece is pushed in, thereby preventing the catch from re-engaging with the notches in the edge of the board, substantially as described, and for the purposes specified.

6. In a drawing-board wherein the board is revolublc, the combination, with the said board, of a catch secured in the frame thereof adapted to engage with notches in the edge of said board, and a slide, D", adapted to engage with a stop or lug connected wlth said catch, whereby said catch may be held out of engagement with said notches when desired, substantially as set forth.

7. The combination of a drawing-board, clamp-bolts Id therein, and levers for operating said clamp-bolts.

S. The combination, with a drawingboard, of the clam pbolts E, extending down through the board, the bell crank levers F, mounted levers II, the shank of which extends up through the board and is provided with a thumbnut, said bell-crank levers H, and connecting-rods I, which connect the levers H to the levers F, whereby the clamp-bolts E are adapted to be operated from the bolt G, sub stantially as set forth.

10. The combination, in a drawing-board, of the clamp bolts E, the bolt part extending down through the board and connecting with the bell-crank levers F, said bell-crank levers F, the springs E, operating to bear upward on said bolt, the connecting-rods I, bell-crank levers H, connected to said bell-crank levers F by said connecting-rods I, and the bolt G, having one arm of each of the bell-crank levers H connected thereto, and athumb-nut, g, on its upper end, by which it is operated, substantially'as described, and for the purposes specified.

11. The combination, in a drawing-board, of the frame A, revoluble board B, frictionplate 0, and set-screwO, whereby said board may be secured rigidly in said frame, substantially as set forth.

12. In a drawing-board, the board of which is revolubly mounted in its frame, the combination of said frame, said board, a frictionplate, and a set-screw, substantially as described, and for the purposes specified.

13. The combination of a frame, A, having an opening therein and having one side adapted to serve as a guide for a T-square, a circular board mounted and adapted to revolve in said opening, and a stop-screw, 0, set in one side of said frame and adapted to come against the edge of said board and thus hold it in any desired position relative to said frame.

In witness whereof I have hereunto set my hand and seal, at Indianapolis, Indiana, this 31st day of March, A. D. 1884.

OnAs. L. THURBER, E. W. BRADFORD. 

